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Date: Fri,  7 Dec 1990 03:18:49 -0500 (EST)
Subject: SPACE Digest V12 #635

SPACE Digest                                     Volume 12 : Issue 635

Today's Topics:
	    HUT Status for 12/04/90 [1800 CST] (Forwarded)
		    Shuttle status at 02/21:25 MET
		    assorted clippings about Astro

Administrivia:

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Date: 5 Dec 90 06:14:50 GMT
From: trident.arc.nasa.gov!yee@ames.arc.nasa.gov  (Peter E. Yee)
Subject: HUT Status for 12/04/90 [1800 CST] (Forwarded)


         HUT Status Report #02
         6 p.m. CST, Dec. 4, 1990
         Spacelab Mission Operations Control
         Marshall Space Flight Center,
         Huntsville, AL
         
         
         The Hopkins Ultraviolet Telescope today produced the first spectrum in
         the far ultraviolet ever obtained for a globular star cluster.
         
         Scientists from The Johns Hopkins University observed M92, a
         collection of ancient stars in the constellation Hercules, about
         25,000 lightyears from Earth.  M92 contains about 100,000 stars, all
         formed about 10 billion years ago, when the Milky Way itself was
         formed.  The cluster is the most metal-poor globular cluster planned
         for observation and among the most metal-poor objects in the Milky Way
         galaxy.  The cluster stars have extremely low abundances of the heavy
         elements, less than one percent of the abundances found in the Sun.
         
         The spectrum resulted from a six-minute observation of M92.  The HUT
         team hopes to observe more than a dozen globular clusters throughout
         the Astro-1 mission, to collect nearly 10 hours of data.
         
         "We have enough data now to do science," said principal investigator
         Arthur Davidsen, a professor of physics and astronomy at Johns
         Hopkins.  "But we got only a fraction of what we're looking for.  We
         have enough data to do a paper; we'd like enough for a thesis."
         
         Davidsen and the rest of the HUT team were elated with the results.
         "There's never been a spectrum of a cluster obtained by rocket;
         they're much too faint," he said.  "And in a few minutes we've gotten
         data at least as good as the first spectrum obtained by IUE at longer
         wavelengths over several hours of observation."
         
         Davidsen said data from the observation will be compared with data
         from other star clusters to learn about the origin and evolution of
         galaxies and stars.  Data from M92 will be compared as well to
         observations of elliptical galaxies, to learn whether the stars in
         these galaxies are fiery ancient suns or blazing young stars.
         
                                          ###

------------------------------

Date: 5 Dec 90 04:14:45 GMT
From: uvaarpa!murdoch!news@mcnc.org  (Greg Hennessy)
Subject: Shuttle status at 02/21:25 MET

During the last shift the ASTRO telescopes became a working
observatory. The shift started with an observation of Capella, which
while none of the 3 UV telescopes were able to observe (the star is so
bright that it confuses the star trackers, which are more sensitive
than the designers thought), the BBXRT was able to use Capella to
align its optics. BBXRT had problem in that it would drift off source,
the origionally thought was a bad gyro, but it turned out to be a
software bug. After the software for the Two Axis Pointing System
(TAPS) was fixed, the tracking was fine. The principle investagator of
BBXRT has pronounced BBXRT was working as designed. In the past shift
BBXRT observed the Large Magellenic Cloud (LMC), the crab nebula, and
several quasars and BL Lac objects. In the incoming shift, they will
be observing the SMC, M87, M81, among others. 

The UV instruments are taking data, but while the star trackers are
working somewhat, they are still rather fussy. It was thought that 4
minutes would be enough for setup before each operation, but a special
operation still needs to be done to insure that the star tracker will
work. A new version of the software will be sent up, and a test on the
star trackers done. The loss of one terminal means that the two
mission scientist have to take turns entering the data, which means
that it takes longer to set up. It seems to take at least 10 minutes
before an observation can begin, and many observations were scheduled
for about 20 minutes or so. These have NOT ben sucessful.  However,
longer exposures have worked. The instuments have been collecting data
for 17% of the time this shift, a dissapointingly low value, but much
better than the 0% of data taken from last shift. UIT was able to take
deep exposures of 3 objecs, M92 (a globular cluster), Betlegeuse, and
Gam Gem (a standard star). In these exposures, UIT achieved about 50%
of the nominal exposure times. Changes will be made to allow more
efficient use of the scheduled time. Collection efficency should rise
to about 50% in the next shift, and if the software patch and test
works, should rise to about 75%, which the loss of a terminal in the
shuttle will make it hard to do better than.  The WUPPE telescope
observed 6 stars, getting nice spectra. The instrument is not properly
calibrated though, due to th eearlier problems. The calibration will
be done this shift, and all of the data taken will be able to be fully
calibrated.  The HUT telescope has observed five stars, but none of
those were stars that they had picked out, rather they were WUPPE
stars. The HUT failed to get any time on any of the 4 stars they
specified. The reason for this is unknown, but WUPPE observes
brightter stars than HUT does, and it may be easier for the star
trackers to track the brighter stars. The HUT is known to be out of
focus a bit, with the stars being 5 arc seconds in diameter, rather
than 2 seconds. The HUT will be focused at the same time as WUPPE, and
this should iimprove their operating efficiency.

During the last shift the UV instruments observed, SS Cyg (a flare
star), M92, the Cygnus Loop super nove remnamt, and my favorite, the
Perseus cluster. Since the Perseus cluster is the UIT's most important
target,this observation will be repeated to try to ensure the best
possible images. 

In the next shift, objects to be observed include M81, M87, the
cluster in Abell 1795, and several sources in the small Magellenic
cloud, Eta Carina, and Ez Cma.


--
-Greg Hennessy, University of Virginia
 USPS Mail:     Astronomy Department, Charlottesville, VA 22903-2475 USA
 Internet:      gsh7w@virginia.edu  
 UUCP:		...!uunet!virginia!gsh7w

------------------------------

Date: 4 Dec 90 21:59:04 GMT
From: uvaarpa!murdoch!news@mcnc.org  (Greg Hennessy)
Subject: assorted clippings about Astro

------------------------------

End of SPACE Digest V12 #635
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